I am not sure exactly what this building is. But the sign and arrows point to the Riverside Ungdomshus, which is a teen center. Website is: http://www.riverside.no/and that is a most red website!

But all the windows are most befouled by bird droppings (an example of the culprits is visible in the upper right of the photo). This area has scores of doves, ducks and gulls circling around, and this building's windows show the result of such.